1. Field
This disclosure relates to a resector for minimally invasive spinal.
2. General Background
Within a vertebra is cancelleous bone “A,” see FIGS. 1A, 1B and 2A and 2B. Surrounding the cancellous bone is a Cortical rim “B,” which is compared to compact bone. Compared to compact bone, cancellous has a higher surface area but is less dense, softer, weaker, and less stiff. It typically occurs at the ends of long bones, proximal to joints and within the interior of vertebrae. Cancellous bone is highly vascular and frequently contains red bone marrow where hematopoiesis, the production of blood cells, occurs. The primary anatomical and functional unit of cancellous bone is the trabecula. The vertebral body “C” includes both compact and cancellous bone.
One method to access the cancelleous bone of a vertebra is by way of a trocar “D.” A trocar is a sharply pointed shaft, usually with a three-sided point. A trocar may be used within a cannula “E,” a hollow tube, designed to be inserted into a vein, artery, bone marrow or body cavity. The word trocar is derived from the French “trois” (three)+“carre” (side).
Procedures used to address damage to vertebral bodies may include vertebroplasty and kyphoplasty, which are medical spinal procedures where bone cement is injected into a damaged or fractured vertebra with the goal of relieving the pain of osteoporotic compression fractures.
Vertebroplasty is typically performed by a spine surgeon or interventional radiologist. It is a minimally invasive procedure and patients usually go home on the same or next day as the procedure. Patients are given local anesthesia and light sedation for the procedure, though it can be performed using only local anesthetic for patients with medical problems who cannot tolerate sedatives well.
During a procedure, bone cement is injected with a biopsy needle into the collapsed or fractured vertebra. Access to the cancelleous bone is via a needle through a resected hole. The bone cement dries and may form a support structure within the vertebra that provides stabilization and strength.
Cervical vertebra pose additional challenges as they are smaller scale than thoracic and lumbar vertebra. For minimally invasive, in particular in the cervical region access cannula may be as small as 11 gauge o.d.